Miniature manual reset circuit breaker



Sept. 28, 1965 H. F. MALONE 3,209,104

MINIATURE MANUAL RESET CIRCUIT BREAKER Filed June 2l, 1963 INVENTOR. /4 /Va/f/@r M/fe.

m44, 9 M 5- www5 United States Patent O 3,209,104 MINIATURE MANUAL RESET CIRCUIT BREAKER Homer F. Malone, Jackson, Mich., assignor, by mesne assignments,y to Mechanical Products, Inc., Jackson, Mich., a corporation of Delaware Filed Junef21-, 19.63,.Ser. No. 289,538 1 Claim. (Cl. 200-122) This invention relates generally to circuit breakers and more particularly to an improved miniature manual reset circuit breaker for use in relatively low current circuits. A need has developed for an improved relatively small manually resettable circuit breaker useable in relatively low current devices, for example, food Waste disposers, electric hand tools, food mixers, meat grinders, blenders, etc. Such a motor protector should provide locked rotor protection as well as overload protection in such devices. In addition it should be capable of protecting static electrical equipment when mounted inherently or intimately relative thereto.

Accordingly, one object of the instant invention is an improved circuit breaker.

Another object is a miniature manually resettable circuit breaker.

Another object is a miniature circuit breaker useable in relatively low current circuits.

Other objects and advantages of the instant invention will be apparent in the following specification, claim and drawings, wherein:

FIGURE l is a top view of a circuit breaker in accordance with an exemplary constructed embodiment of the of the instant invention;

FIGURE 2 is a cross-sectional view taken substantially along the line 2-2 of FIGURE l;

FIGURE 3 is a cross-sectional view taken substantially along the line 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional view taken substantially along the line 4-4 of FIGURE 2; and,

FIGURE 5 is a view of the manually operable reset slide of the circuit breaker, and

FIG. 6 is a fragmentary view similiar to FIG. 2 showing the separable contacts locked in the open condition.

An improved circuit breaker in accordance with the instant invention features an improved heat transfer relationship between a snap acting bimetallic blade and an integral heater. The blade and heater extend in close parallel relationship, a combination reset slide and manual operatorv of novel configuration being associated therewith to maintain the contacts of the circuit breaker in the disengaged condition upon the occurrence of a predetermined temperature or electrical condition. The manual operator is movable to a reset condition to reenergize an electrical circuit containing the circuit breaker.

More particularly an improved circuit breaker 10 cornprises an upper casing 12 and a lower casing 14 that are retained together by a generally U-shaped retainer 16 and rivet 52. The retainer 16 has a threaded ferrule portion 20 thereon to facilitate attachment of the circuit breaker to a panel board or the like when it is mounted externally of the device being protected.

As best seen in FIGURE 4 of the drawings, a generally fiat heater 30 has a terminal portion 32 that extends through a complementary aperture 34 in the lower case 14 for connection to one side of an electric-al circuit. The heater 30 has an intermediate portion 36 of serpentine configuration, the electrical characteristics of which are dictated by the application of the circuit breaker 10.

A fixed contact 40 is secured to an inner end portion 42 of the heater 30. The heater 30 has a plurality of apertures 44, 46, and 48 for the acceptance of a plurality of rivets 50, 52 and 54, respectively. The rivets 50 and 54 retain the electrically energized components of the circuit 3,209,104 Patented Sept. 28, 1965 ICC breaker 10 in the assembled condition as a sub-assembly whereasthe rivet 52 retains' the c-ase portions 12, 1'4 and retainer 16 in the assembled condition.

As best seen' in FIGURE 2y an insulating spacerf60 is stacked on the heaterf30A and has an upwardly extending boss 62 that is accepted in a complementary aperture 64y in a snap acting bimetallic blade 66. The blade 66 has a non-developable surface 68- therein and a movable contact 70 at a free end thereof that is engageable with the fixed contact 40 as will be described.

A generally forked blade control plate overlies a fixed end portion 81 of the snap blade 66 to control movement thereof. The control blade 80'has a terminal portion 82 that extends outwardly through a complementary aperture 84 in the upper case12 for connection to the other side of an electrical circuit containing the circuit breaker 10.

An insulating combination reset slide and manual operator having a stern portion 92 for the acceptance of a button 94 is slidably mounted for movement in a plane that lies between the blade 66 and heater 30. The slide 90 has an arm portion 96 that functions as a guide and retainer for an operating spring 98. The spring 98 is seated in a complementary channel 100 in the case portions 12 and 14. f

In accordance with one feature of the instant invention the manual operator 90 has a relatively large central aperture 102 that provides for heat transfer between the blade 66 and heater 30.

The slide 90 has an end portion 104 that is normally engaged with the movable contact 70. Thus, when the contacts 70 and 40 are in the closed condition, the slide 90 is biased against the contact 70 by the spring 98. When the contacts 70 and 40 separate due to snap action of the blade 66 the slide 90 moves to the left as seen in the d rawings, appropriate shoulders 106 and 108 thereon limiting movement due to engagement with an end wall 110 on the casing 14.

When the snap acting blade 66 cools it of course tends to sn-ap to the condition shown in FIGURE 2 of the drawings. However, the contact 70 is precluded from movement into engagement with the contact 40 by the end portion 104 of the slide 90. When the slide is moved from between the contacts 70 and 40, as by manually pushing on the reset button 94, a circuit through the circuit breaker is again completed.

From the foregoing description it should be apparent that the circuit breaker of the instant invention is relatively small and compact. It provides for lock out of the separable contacts thereof Without adversely affecting the heat transfer relationship between the heater 30 and blade 66. In addition, both the electrically energized components and the insulating slide comprise a sub-assembly that is easily integrated into a casing.

It is to be understood that the specific construction of the miniature manual reset circuit breaker herein disclosed and described is presented for the purpose of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claim.

What is claimed is:

A miniature manual reset circuit breaker comprising an insulating enclosure,

a first terminal extending exteriorly of said casing,

a generally flat heater having one end electrically con- -nected to said first terminal,

a fixed contact mechanically supported by and electrically connected to said heater at the other end thereof,

a substantially flat thermally responsive snap-acting blade extending generally parallel to said heater in spaced heat transfer relation thereto, said blade a central aperture to facilitate heat transfer between having, said heater and blade, a reset portion extending a xed end portion mechanically connected to the one exteriorly of said enclosure and a lockout portion end of said heater but electrically insulated therenormally engaged with said movable contact and from, l 5 movable between said contacts upon opening thereof, a movable contact on the other end of said blade enand resilient means for normally biasing said slide to' gageable with said xed contact, the lockout condition.

a second terminal extending exteriorly of said enclosure and electrically connected to the fixed end of said BERNARD A. GILHEANY, Primary Examiner. blade,

a generallyflat reset slide lying in a plane extending N0 references cltedbetween said heater and blade, said slide having, 

